ul,ol{
    list-style: none;
    padding-inline-start: 0;
}

a{
    color: black;
}

a:hover{
    text-decoration: none;
}

#course>ul>li{
    padding: 10px 0;
}


/**给左半部分的a标签添加样式**/
#course li:hover{
    background-color: WhiteSmoke;
}

.active{
    background-color: ghostwhite;
}

.divider{
    border-bottom: 1px solid lightgray;
}

small{
    color: #d4521a;
}